1491665531 has 4 divisors (see below), whose sum is σ = 1493950512. Its totient is φ = 1489380552.

The previous prime is 1491665519. The next prime is 1491665557. The reversal of 1491665531 is 1355661941.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1491665531 - 2³⁰ = 417923707 is a prime.

It is a super-2 number, since 2×1491665531² = 4450132112747023922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1491665501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1141511 + ... + 1142816.

It is an arithmetic number, because the mean of its divisors is an integer number (373487628).

Almost surely, 2^1491665531 is an apocalyptic number.

1491665531 is a deficient number, since it is larger than the sum of its proper divisors (2284981).

1491665531 is an equidigital number, since it uses as much as digits as its factorization.

1491665531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2284980.

The product of its digits is 97200, while the sum is 41.

The square root of 1491665531 is about 38622.0860518952. The cubic root of 1491665531 is about 1142.5901736034.

The spelling of 1491665531 in words is "one billion, four hundred ninety-one million, six hundred sixty-five thousand, five hundred thirty-one".